Fuse-alarm



Jan. 1, 1963 G. L. GLUECKERT 3,071,760

FUSE-ALARM Filed sept. 19, 1958 F|G.| F' G2 w/ v 4 M/ W .M @1m 2 /wis m 6 .l w 6 5 G. a. U\\ 2 am M n lll U\\ M.. M/ ...IN F mi M/ m y w mm2, I/ l w l.//Jw/////w w.. E IYS 2J 4J :la H M O 5 4 G. l/ H m i. 2L 4A\ 1/0 Ilu INVENTOR 57 GEORGE L. GLUECKERT BY @,gZ/n ATTORNEYS United States Patent 3,071,760 FUSE-AL George L. Glueckert, Detroit, Mich. (8478 Hazelton, Dearborn 6, Mich.) Filed Sept. 19, 1958, Ser. No. '762,060 3 Claims. (Cl. S40-250) This invention relates to protective devices for electrical circuits of the type which includes a fuse member adapted to be ruptured when heated by the overloading of the circuit.

It is an important object of this invention to provide a fuse plug which is provided with means for creating an audible noise when the fuse in the plug has blown.

It is a further object of this invention to provide a fuse plug provided with a primary or fuse circuit including a replaceable fuse and a high resistance secondary or signal circuit shunted across the fuse whereby when the fuse blows, the current will flow through the secondary circuit .at which time it will start and continue to emit an audible signal until the fuse plug is removed or its replaceable fuse is replaced.

It is still a further object of this invention to provide a combination fuse and alarm plug which is simple and compact in construction, economical of manufacture, and efficient in operation.

`Other objects, features and advantages of this invention will be apparent from the following detailed description and appended claims, reference being had to the accompanying drawing forming a part of the specification wherein like reference numerals designate corresponding parts of the several views.

In the drawing:

FIG. 1 is a top plan view of a fuse-alarm plug made in accordance with the principles of the invention;

FIG. 2 is an elevational sectional view of the structure illustrated in FIG. l, taken along the line 2-2 thereof, and looking in the direction of the arrows;

FIG. 3 is a horizontal sectional view of the structure illustrated in FIG. 2, taken along the line 3-3 thereof, and looking in the direction of the arrows;

FIG. 4 is an elevational View of the structure illustrated in FIG. l, taken along the line 4 4 thereof, and looking in the direction of the arrows;

FIG. 5 is a side elevational view of a modified fusealarm made in accordance with the principles of the invention;

FIG. 6` is an end elevational View of the structure illustrated in FIG. 5, taken along the line 6--6 thereof.

Referring now to the drawing wherein is shown a first embodiment in FIGS. l, 2, 3 and 4, the numeral 16* generally represents an insulator body which is made from any suitable insulating material. The body 10 cornprises the upper cylindrical portion 11 which is enclosed on the -lower end thereof by the lower end wall 12 and which is open at the upper end thereof. The insulator body 10 further includes the lower reduced portion 13 which forms a fuse cup and which is integral with the upper body portion 11. The fuse cup portion 13 is open at the lower end thereof and is provided with the usual threaded metallic contact shell as the brass sleeve 14.

As shown in FIG. 2, the lower end of the fuse cup body portion 13 is enclosed by an insulator end cap generally `designated -by the numeral 15 and which comprises the annular end plate portion 16 and the integral inwardly extended sleeve portion v17. The end cap 15 is adapted to be `seated in the lower enlarged end of the stepped bore 18 in the fuse cup 13 as by means of a slip lit. FiXedly mounted in the opening 19 in the end plate 16 is a metallic contact generally designated by the numeral 20. The contact 20 includes the neck portion 21 which is received in the opening y19 and the integral inner and outer contact plates 22 and 23, respectively.

As shown in FIG. 2, a conventional replaceable cartridge fuse 24 is seated on the contact plate 22 inside of the fuse cup body portion 13. The upper end of the fuse 24 is in electrical contact with the metallic contact member generally indicated by the numeral 25. The contact member 25 is xedly mounted in the opening 26 in the lower wall 12 of the upper body portion. The contact member 25 includes the neck portion 27 positioned in the opening 26 and the integral lower end upper contact plates 28 and 29, respectively. The contact member 25 is electrically connected by means of the conductor or lead wire Sil to the metallic contact shell 14. The lead wire 30 passes through the passageway 31 formed in the fuse cup body portion 13. It will be seen that a primary or fused current feed circuit is thus formed by the aforementioned structure. This primary circuit comprises the contact 20, the fuse 24, the contact 25, the conductor 30 and the ycontact shell 14.

As shown in FIG. 2, the fuse plug is also provided with a high resistance secondary or signal current circuit which is connected in parallel with or shunted across the primary current feed circuit as more fully described hereinafter. The secondary or signal circuit is connected at one end thereof to the contact plate 29 by means of the conductor or lead wire 32. The conductor 32 is connected at the other end thereof to a flasher or a thermal circuit make and break device constructed as described hereinafter. The flasher includes the fixedly mounted strip of metal 33 which is supported inside of the body portion 11 on the lower wall 12 by any suitable means as by the supports 34. The aforementioned flasher further includes the flexible resilient bi-metallic plate 35 which is disposed above the metallic strip 33 and is supported at one end thereof by any suitable means as the support 36. A high resistance heater coil as 37 is mounted around the bi-metallic plate 35 and this coil is connected at one end thereof to the plate 35 as at the point 38. The other end of the resistance coil 37 is connected by the lead wire or conductor 39 to the conductor plate 33. The free movable left end of the conductor plate 35 carries a contact 40 which is disposed above the contact 41 on the conductor plate 33. The contacts 40 and 41 are shown in the open or standby condition which they .assume during the normal operation of the fuse. It will be seen that the resistance or heater coil 37 is connected in parallel with the contacts 40 and 41 when these contacts are closed.

As shown in FIG. 2, the movable flasher contact carrier plate 35 is connected by means of the conductor or lead wire 42 to one end of the solenoid coil 44 as at the contact point 43. Operatively mounted inside of the solenoid coil 44 is the soft iron core 44a and this coil rests in the U-shaped soft iron saddle 45. The saddle 45 comprises the bight portion 46 and the two integral upwardly extended leg portions 47 which are each provided on the upper ends thereof with a horizontal outwardly extended lip or 48. The saddle lips 48 are adapted to be seated in the diametrically oppositely disposed slots 49 formed in the upper edge of the body portion 11 as shown in F-IG. 3. The fuse plug upper body portion 11 is enclosed by the soft iron diaphragm 50 which rests on the saddle 45 and which is held in place by means of the snap-on annular cover or retainer ring 51. The other end of the solenoid coil 44 is connected as at the point 52 to the bronze spring contact 53 which passes downwardly through the passageways 54 and 55 in the body portion 13 and which contacts the lower end of the fuse 24 at the point marked 56.

The fuse plug of the present invention may be easily and quickly installed in :a -fuse box by merely removing the old prior art type fuse and replacing it with a fuse plug of the present invention. It will be seen that the. primary circuit through the parts 23, 24, 25, 3i) and 14- form the primary current feed circuit and that the other' circuit through the solenoid buzzer is connected in paral lel thereto. Since the secondary or alarm circuit is of aV high resistance, the current in the power line will flow through the primary circuit and the secondary alarm circuit will merely be in a standby condition since it will not pull enough current to operate the alarm. However, when the fuse 24 blows, a suicient current will then pass through the secondary or alarm circuit to actuate the: solenoid buzzer 44 to produce a low signal. The heater coil 37 will Warm the movable bi-metallic contact carrying plate 35 of the flasher whereby this arm will bend down from the standby position of FIG. 2 and the contacts 40 and 41 will be engaged with each other thereby shunting the alarm circuit around the resistance flasher coil 37 to actuate the signal circuit and cause a loud signal. The plate 35 offers less resistance to the flow of current than the resistance coil 37 and when the contacts 40 and 41 are closed an increased amount of current will llow through the solenoid coil 44 to actuate the same to cause a loud signal. The contact carrier plate 35 then cools and bends up to its standby position and the contacts 40 and 41 are separated and the coil 37 is then again heated up and the former operation is repeated.v The fuse alarm of the invention is adapted to operate on alternating current only.

It will be seen that the secondary or signal circuit will continue to operate until the fuse alarm is removed or its fuse 24 is replaced by a new fuse. The intermittent action of the tone of the audible noise when the fuse is blown makes it impossible for a person to overlook or ignore the blown fuse 24. Accordingly, the fuse plug of the present invention will result in a great saving of life and property since the fact that the fuse has blown in a circuit will be immediately noticeable. The fuse plug ofthe present invention will decrease losses which have occurred in the past through blown fuses on sump pumps, deep freeze circuits, well pumps, heating systems, and hot water control circuits because of no knowledge that a fuse has blown. Much inconvenience has been suffered heretofore by those who without their knowledge had blown fuses on circuits of the aforementioned types.

FIGS. and 6 illustrates a slightly modified embodiment of the fuse plug of the present invention. The embodiment of FIGS. 5 and 6 is constructed the same as the embodiment of FIGS. l through 4 except that the lower body portion 13 of the first embodiment has been replaced with a differently shaped lower body portion 57 for the purpose of holding a longer cartridge type replaceable fuse for use in circuits where the fuse is to be snapped in place. The fuse body portion 57 is provided with the horizontal hole 58 therethrough in which is removeably disposed the replaceable cartridge fuse generally indicated by the numeral 59 and which' is releasably secured in the body portion 57 by means of the set screws 60. The fuse 59 is provided with the usual metal end caps 61 and 62. for snapping the fuse in place in the usual mating clips in a circuit fuse box. The conductors 30a and 53a correspond to and function similarly to the conductors 30 and 53 and would be made from a suitable spring metal. It will be seen that the embodiment of FIGS. 5 and 6 is provided with a first current carrying circuit through the fuse 59 and that the fuse body portion 11a would retain therein an alarm circuit identical to the secondary or alarm circuit in the embodiment of FIG. 2. The alarm circuit in the body portion 11a would be connected in parallel or shunted across the fuse 59 by means of the spring contacts 30a and 53a in the same manner as in the embodiment of FIG. 2. The embodiment of FIGS. 5 and 6 would function in the same Way as the embodiment of FIG. 2.

`It"will be seen that the asherof Vthe present invention lessens the resistance in the signal circuit when the contacts 40 and 41 are engaged whereby a greater flow of current Will pass through the solenoid coil 44 and the diaphragm 50 will be vibrated to produce a high pitched sound. When the heater coil 37 is in the circuit and is not by-passed by the contacts 40 and 41, a lesser amount of current will ilow through the secondary signal circuit and the diaphragm 50 vwill be vibrated to produce a lower pitched sound.

While it will be apparent that the preferred embodiments of the invention herein disclosed are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What I claim is:

l. In a unitary, combined fuse and alarm device for protecting an electrical circuit, an insulator fuse casing having a first portion and a second portion, said rst portion having spaced contacts exposed to the surface thereof, a primary current feed circuit carried in said first portion including a fuse element electrically connected across said contacts, a secondary signal circuit carried in said second portion having means in series therewith for producing an audible signal, which means and said secondary circuit are substantially completely within said casing, said secondary signal circuit being shunted across said primary circuit and having a sufticiently high resistance that said secondary signal circuit will be inoperative when said fuse element is intact, and means in said second portion for intermittently varying said signal when it is activated by a rupture of said fuse element, said means comprising a resistance element in said signal circuit and thermally responsive switch means in said signal circuit adjacent said element, said switch means being movable lbetween open and closed positions in thermal response to a variation in the temperature of said resistance element, said switch means intermittently varying the current in said signal circuit and thereby varying the temperature of said resistance element.

2. A `device as set forth in claim l, wherein said fuse element comprises a replaceable cartridge type fuse having opposed metal contact ends, said contact ends being connected to said surface contacts, said fuse being mounted transversely of said first casing portion with said metal contact ends extending beyond said rst casing portion, whereby said unitary fuse and alarm device is detachably connectable to the connector clips of a standard, cartridge-type fuse box.

3. In a unitary, combined fuse and alarm device for protecting an electrical circuit, an insulator fuse casing having a rst portion and a second portion, said rst portion having spaced contacts exposed to the surface thereof, a primary current feed circuit carried in said rst portion including a fuse element electrically connected across said contacts, a secondary signal circuit carried in said second portion having means in series therewith for producing an audible signal, which means and said secondary circuit are substantially completely within said casing, said secondary signal circuit being shunted across said primary circuit and having a sufficiently high resistance that said secondary signal circuit will be inoperative when said fuse element is intact, and means in said second portion for intermittently varying the said signal when said signal circuit is activated by a rupture of said fuse element, said means including a resistance in series with said signal clrcuit, a bimetallic arm adjacent said resistance, one end of said arm being electrically connected to one end of said resistance, the other end of said arm bearing an electrical contact movable into engagement with the other end of said resistance, the said arm thereby intermittently blocking said resistance from said signal circuit by intermittently forming a shunt thercacross and causing an intermittent variation of the current in said signal circuit.

(References on following page) References Cited in the le of this patent UNITED STATES PATENTS White Oct. 14, 1890 Sleeper June 10, 1930 Cole Sept. 19, 1933 Linton July 2, 1940 6 Chttum June 24, 1947 vLoporto Apr. 25, 1950 Duerkob Sept. 30, 1958 Swing et al. Oct. 7, 1958 FOREIGN PATENTS Australia June 10, 1954 

1. IN A UNITARY, COMBINED FUSE AND ALARM DEVICE FOR PROTECTING AN ELECTRICAL CIRCUIT, AN INSULATOR FUSE CASING HAVING A FIRST PORTION AND A SECOND PORTION, SAID FIRST PORTION HAVING SPACED CONTACTS EXPOSED TO THE SURFACE THEREOF, A PRIMARY CURRENT FEED CIRCUIT CARRIED IN SAID FIRST PORTION INCLUDING A FUSE ELEMENT ELECTRICALLY CONNECTED ACROSS SAID CONTACTS, A SECONDARY SIGNAL CIRCUIT CARRIED IN SAID SECOND PORTION HAVING MEANS IN SERIES THEREWITH FOR PRODUCING AN AUDIBLE SIGNAL, WHICH MEANS AND SAID SECONDARY CIRCUIT ARE SUBSTANTIALLY COMPLETELY WITHIN SAID CASING, SAID SECONDARY SIGNAL CIRCUIT BEING SHUNTED ACROSS SAID PRIMARY CIRCUIT AND HAVING A SUFFICIENTLY HIGH RESISTANCE THAT SAID SECONDARY SIGNAL CIRCUIT WILL BE INOPERATIVE WHEN SAID FUSE ELEMENT IS INTACT, AND MEANS IN SAID SECOND PORTION FOR INTERMITTENLY VARYING SAID SIGNAL WHEN IT IS ACTIVATED BY A RUPTURE OF SAID FUSE ELEMENT, SAID MEANS COMPRISING A RESISTANCE ELEMENT IN SAID SIGNAL CIRCUIT AND THERMALLY RESPONSIVE SWITCH MEANS IN SAID SIGNAL CIRCUIT ADJACENT SAID ELEMENT, SAID SWITCH MEANS BEING MOVABLE BETWEEN OPEN AND CLOSED POSITIONS IN THERMAL RESPONSE TO A VARIATION IN THE TEMPERATURE OF SAID RESISTANCE ELEMENT, SAID SWITCH MEANS INTERMITTENLY VARYING THE CURRENT IN SAID SIGNAL CIRCUIT AND THEREBY VARYING THE TEMPERATURE OF SAID RESISTANCE ELEMENT. 